Understanding regions?

sorry for these questions, but im somewhat new to wii, but i really try to read around.

I bought a modded japanese wii in Vietnam.
I looked at over there, and tested some games, they work fine with the modchip. However my wii is all in japanese.
Now im back in the states, and im wondering..
wats my region? does it auto update by time zone or what.

from wat ive seen lately, there are only 3 regions? I assume, US, jap, edit: third region is PAL.(which is what?)
just a guess.
anyhow, would my region be japanese or english(us).

also: will pal region isos work on jap wii's?
it seems, my jap wii, when a bootlegged game is inserted, its all in English. so does it mean it can play US Games? im not understanding this.

pal = europe. i have no idea how to change the language but i think you stuck with jap, depending on what mod chip you have you should be able to play different region games, but make sure not to update from different region game diska nd use brick blocker